There is a strong demand to reduce the size of electronic systems. The size reduction is especially desirable in mobile electronics where space is a premium, but is also desirable in servers that are placed in big data centers since it is important to squeeze in as many servers as possible in fixed-size real estate.
One of the largest components in electronic systems is a voltage regulator (also referred to as a power regulator) that provides power to integrated chips, such as processors, memory devices (e.g., a dynamic random access memory (DRAM)), radio-frequency (RF) chips, WiFi combo chips, and power amplifiers. A power regulator often includes a large number of bulky off-chip components, and these components limit the size reduction of power regulators.
One type of power regulator that does not require a large number of bulky off-chip components is a switched capacitor regulator. A switched capacitor regulator can use capacitors that are integrated “on-chip,” which tend to be significantly smaller than off-chip components. Therefore, an “on-chip” switched capacitor regulator can be significantly smaller than other types of regulators that use off-chip components, such as a buck regulator. An on-chip switched capacitor regulator is desirable also because it is known to be efficient even at a high voltage conversion ratio as long as the voltage conversion ratio is an integer number.
Unfortunately, the efficiency of a switched capacitor regulator is limited due to parasitic capacitances that are inevitably present in circuits. Therefore, there is a strong need to provide a power regulator that is capable of attaining a high efficiency even in the presence of parasitic capacitances.